Tài liệu đề khảo sát chất lượng môn vật lý 8

Hä vµ tªn:......................................... Líp: 8... §iÓm §Ò kh¶o s¸t chÊt lîng M«n: VËt lý. Thêi gian: 30 phót Lêi nhËn xÐt cña gi¸o viªn ®Ò a I. PhÇn tr¾c nghiÖm : (3 ®iÓm) C©u 1: Khi chØ chÞu t¸c dông cña 2 lùc. CÆp lùc nµo sau ®©y lµm vËt ®ang ®øng yªn sÏ tiÕp tôc ®øng yªn? A. Hai lùc cïng cêng ®é, cïng ph¬ng. B. Hai lùc cïng ph¬ng nhng ngîc chiÒu. C. Hai lùc cïng cêng ®é, cïng ph¬ng, cïng chiÒu. D. Hai lùc cïng cêng ®é, cïng ph¬ng, ngîc chiÒu. C©u 2: VËt nh thÕ nµo khi chØ chÞu t¸c dông cña hai lùc c©n b»ng? A. VËt ®ang ®øng yªn sÏ chuyÔn ®éng nhanh dÇn. B. VËt ®ang chuyÓn ®éng sÏ dõng l¹i. C. VËt ®ang ®øng yªn sÏ ®øng yªn, hoÆc vËt ®ang chuyÓn ®éng sÏ chuyÓn ®éng th¼ng ®Òu m·i. D. VËt ®ang chuyÓn ®éng ®Òu sÏ kh«ng cßn chuyÓn ®éng ®Òu n÷a. C©u 3: Hµnh kh¸ch ngåi trªn xe « t« ®ang chuyÓn ®éng bçng thÊy m×nh bÞ nghiªng ngêi sang phÝa tr¸i, chøng tá xe: A. ®ét ngét rÏ sang tr¸i. B. ®ét ngét rÏ sang ph¶i. C. ®ét ngét t¨ng tèc ®é. D. ®ét ngét gi¶m tèc ®é. C©u 4: Trong trêng hîp lùc xuÊt hiÖn sau ®©y,trêng hîp nµo kh«ng ph¶i lµ lùc ma s¸t? A. Lùc xuÊt hiÖn khi ta kÐo d·n 1 lß xo. B. Lùc xuÊt hiÖn lµm mßn ®Õ giµy. C. Lùc xuÊt hiÖn khi ta ®Èy xe hµng. D. Lùc xuÊt hiÖn khi ta trît tuyÕt. C©u 5: Trong c¸c c¸ch lµm sau ®©y, c¸ch nµo lµm gi¶m ®îc lùc ma s¸t? A. T¨ng lùc Ðp lªn bÒ mÆt tiÕp xóc. B. T¨ng diÖn tÝch bÒ mÆt tiÕp xóc. C. T¨ng ®é nh½n gi÷a c¸c bÒ mÆt tiÕp xóc. D. T¨ng ®é nh¸m cña mÆt tiÕp xóc. C©u 6: Muèn gi¶m ¸p suÊt ta ph¶i lµm nh thÕ nµo? A. T¨ng ¸p lùc, gi¶m diÖn tÝch bÞ Ðp. B. T¨ng ¸p lùc, t¨ng diÖn tÝch bÞ Ðp. C. Gi¶m ¸p lùc, gi¶m diÖn tÝch bÞ Ðp. D. Gi¶m ¸p lùc, t¨ng diÖn tÝch bÞ Ðp. II. PhÇn tù luËn (7 ®iÓm) ////////////////// C©u 1: (2,5 ®iÓm) Cho mét qu¶ cÇu ®îc treo trªn sîi d©y(h×nh vÏ) Hái cã nh÷ng lùc nµo t¸c dông lªn qu¶ cÇu? H·y biÓu diÔn c¸c vÐc t¬ lùc t¸c dông lªn qu¶ cÇu. ........................................................................................................ ........................................................................................................ ......................................................................................................... ......................................................................................................... ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. C©u 2: (1,5 ®iÓm) Gi¶i thÝch t¹i sao khi nh¶y tõ trªn cao xuèng ch©n ta bÞ gËp l¹i? ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. C©u 4: (3 ®iÓm) Mét ngêi cã khèi lîng 45kg ®øng trªn sµn nhµ. BiÕt diÖn tÝch cña 1 bµn ch©n tiÕp xóc víi mÆt sµn lµ 150cm2. H·y tÝnh ¸p suÊt cña ngêi ®ã t¸c dông lªn mÆt sµn khi ngêi ®ã: a) §øng mét ch©n. b) §øng hai ch©n. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. Hä vµ tªn:......................................... §Ò kh¶o s¸t chÊt lîng Líp: 8... M«n: VËt lý. Thêi gian: 30 phót §iÓm Lêi nhËn xÐt cña gi¸o viªn ®Ò b I. PhÇn tr¾c nghiÖm : (3 ®iÓm) H·y chän ®¸p ¸n ®óng nhÊt C©u 1: §Æc ®iÓm cña hai lùc c©n b»ng cïng t¸c dông lªn mét vËt lµ: A. Hai lùc cïng cêng ®é, cïng ph¬ng. B. Hai lùc cïng ph¬ng nhng ngîc chiÒu. C. Hai lùc cïng cêng ®é, cïng ph¬ng, ngîc chiÒu. D. Hai lùc cïng cêng ®é, cïng ph¬ng, cïng chiÒu. C©u 2: VËt nh thÕ nµo khi chØ chÞu t¸c dông cña hai lùc c©n b»ng? A. VËt ®ang ®øng yªn sÏ chuyÓn ®éng th¼ng. B. VËt ®ang chuyÓn ®éng sÏ chuyÓn ®éng sang híng kh¸c. C. VËt ®ang ®øng yªn sÏ ®øng yªn, hoÆc vËt ®ang chuyÓn ®éng sÏ chuyÓn ®éng th¼ng. D. VËt ®ang ®øng yªn sÏ ®øng yªn, hoÆc vËt ®ang chuyÓn ®éng sÏ chuyÓn ®éng th¼ng ®Òu m·i. C©u 3: Hµnh kh¸ch ngåi trªn xe « t« ®ang chuyÓn ®éng bçng thÊy m×nh bÞ nghiªng ngêi sang phÝa ph¶i, chøng tá xe: A. ®ét ngét rÏ sang ph¶i. B. ®ét ngét rÏ sang tr¸i. C. ®ét ngét t¨ng tèc ®é. D. ®ét ngét gi¶m tèc ®é. C©u 4: Trong trêng hîp lùc xuÊt hiÖn sau ®©y,trêng hîp nµo kh«ng ph¶i lµ lùc ma s¸t trît? A. Lùc xuÊt hiÖn khi ®Èy thïng hµng. B. Lùc xuÊt hiÖn khi «t« phanh gÊp. C. Lùc xuÊt hiÖn khi ta ®Èy xe hµng. D. Lùc xuÊt hiÖn khi ta trît tuyÕt. C©u 5: Trong c¸c c¸ch lµm sau ®©y, c¸ch nµo lµm t¨ng ®îc lùc ma s¸t? A. T¨ng ®é nh¸m cña mÆt tiÕp xóc. B. T¨ng diÖn tÝch bÒ mÆt tiÕp xóc. C. T¨ng ®é nh½n gi÷a c¸c bÒ mÆt tiÕp xóc. D. T¨ng lùc Ðp lªn bÒ mÆt tiÕp xóc. C©u 6: Muèn t¨ng ¸p suÊt ta ph¶i lµm nh thÕ nµo? A. T¨ng ¸p lùc, gi¶m diÖn tÝch bÞ Ðp. B. T¨ng ¸p lùc, t¨ng diÖn tÝch bÞ Ðp. C. Gi¶m ¸p lùc, gi¶m diÖn tÝch bÞ Ðp. D. Gi¶m ¸p lùc, t¨ng diÖn tÝch bÞ Ðp. II. PhÇn tù luËn (7 ®iÓm) C©u 1: (2,5 ®iÓm) Cho mét cuèn s¸ch ®Æt trªn bµn (h×nh vÏ) Hái cã nh÷ng lùc nµo t¸c dông lªn cuèn s¸ch? H·y biÓu diÔn c¸c vÐc t¬ lùc t¸c dông lªn cuèn s¸ch. ........................................................................................................ ///////////////// ........................................................................................................ ......................................................................................................... ......................................................................................................... ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. C©u 2: (1,5 ®iÓm) Gi¶i thÝch t¹i sao khi c¸n bóa láng, cã thÓ lµm chÆt c¸n bóa b»ng c¸ch gâ m¹nh ®u«i c¸n xuèng ®Êt? ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. C©u 4: (3 ®iÓm) Mét ngêi cã khèi lîng 60kg ®øng trªn sµn nhµ. BiÕt diÖn tÝch cña 1 bµn ch©n tiÕp xóc víi mÆt sµn lµ 200cm2. H·y tÝnh ¸p suÊt cña ngêi ®ã t¸c dông lªn mÆt sµn khi ngêi ®ã: c) §øng mét ch©n. d) §øng hai ch©n. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ®¸p ¸n ®Ò kh¶o s¸t chÊt lîng ®Ò a I. phÇn tr¾c nghiÖm: Mçi c©u tr¶ lêi ®óng ®¹t 0,5 ®iÓm C©u 1 2 3 4 5 6 §¸p ¸n D C B A C D ii.phÇn tù luËn: C©u 1: - Gåm hai lùc t¸c dông lªn qu¶ cÇu: Träng lùc vµ lùc c¨ng cña sîi d©y. (1®) - BiÓu diÔn lùc ®óng nh h×nh vÏ (1,5 ®) ////////////////// T A C©u 2: (1,5 ®) P Khi nh¶y tõ trªn cao xuèng, ch©n ch¹m ®Êt bÞ dõng ngay l¹i, nhng ngêi vÉn cßn chuyÓn ®éng vÒ phÝa díi theo qu¸n tÝnh nªn lµm ch©n gËp l¹i. C©u 3: Tãm t¾t: m= 45kg; S1 = 150cm2=0,015m2; S2=2.S1=0,03m2 P1=? P2=? (0,5 ®) Gi¶i: ¸p lùc cña ngêi ®ã lªn sµn nhµ lµ: F= 10.m = 10.45 = 450 (N) (0,5 ®) ¸p suÊt cña ngêi ®ã khi ®øng 1 ch©n lµ: P1 = F/ S1 = 450/0,015 = 30 000 (Pa) (1 ®) ¸p suÊt cña ngêi ®ã khi ®øng 2 ch©n lµ: P2 = F/ S2 = 450/0,03 = 15 000 (Pa) (1 ®) §¸p sè: ®¸p ¸n ®Ò kh¶o s¸t chÊt lîng ®Ò b I. phÇn tr¾c nghiÖm: Mçi c©u tr¶ lêi ®óng ®¹t 0,5 ®iÓm C©u 1 2 3 4 §¸p ¸n C D B C 5 A 6 A ii.phÇn tù luËn: C©u 1: - Gåm hai lùc t¸c dông lªn cuèn s¸ch: Träng lùc vµ lùc n©ng cña mÆt bµn. - BiÓu diÔn lùc ®óng nh h×nh vÏ (1,5 ®) (1®) A N ///////////////// C©u 2: (1,5 ®) P Khi gâ m¹nh ®u«i c¸n bóa xuèng ®Êt, c¸n bóa ®ét ngét bÞ dõng l¹i, nhng ®Çu bóa vÉn tiÕp tôc chuyÓn ®éng xuèng phÝa díi do cã qu¸n tÝnh, nªn ®Çu bóa ngËp chÆt vµo c¸n bóa. C©u 3: Tãm t¾t: m= 60kg; S1 = 200cm2=0,02m2; S2=2.S1=0,04m2 P1=? P2=? (0,5 ®) Gi¶i: ¸p lùc cña ngêi ®ã lªn sµn nhµ lµ: F= 10.m = 10.60 = 600 (N) (0,5 ®) ¸p suÊt cña ngêi ®ã khi ®øng 1 ch©n lµ: P1 = F/ S1 = 600/0,02 = 30 000 (Pa) (1 ®) ¸p suÊt cña ngêi ®ã khi ®øng 2 ch©n lµ: P2 = F/ S2 = 600/0,04 = 15 000 (Pa) (1 ®) §¸p sè: